This invention relates to a bus bar arrangement for a heatable vehicle window (e.g., vehicle windshield) including at least first and second heating zones. In particular, this invention relates to a bus bar arrangement including first and second spaced apart top bus bar portions which work in conjunction with a bottom bus bar to define at least first and second heating zones on a vehicle window.
Heatable windows are known in the art. For example, see U.S. Pat. Nos. 5,434,384 and 4,782,216, the disclosures of which are hereby incorporated herein by reference. Heatable windows conventionally include first and second conductive bus bars in electrical contact with a transparent conductive coating including an electroconductive layer. The electroconductive layer generates heat when electric current is passed therethrough. In such a manner, snow and ice may be melted from vehicle windows such as windshields, backlites, sidelites, and/or the like. Windows may also be defogged in such a manner.
In conventional heatable windows, first and second bus bars are often located in spaced apart relation proximate opposite edges of the window. Unfortunately, this type of design often requires the electrical connector for the top bus bar to exit the window at the top edge thereof, and the electrical connector for the bottom bus bar to exit the window at the bottom edge thereof. This is undesirable in that it is much more convenient if both connectors (i.e., for both bus bars) are located along the same edge/side of the window.
In an attempt to overcome the aforesaid problem, U.S. Pat. No. 4,820,902 discloses first and second conductive leads/extensions arranged from opposite sides of the top bus bar heading down the respective sides of the windshield and across the bottom side/edge of the same. In such a manner it is possible to locate the electrical connectors for both bus bars at the bottom edge/side of the windshield. Unfortunately, the design of the ""902 patent is undesirable in that the entire viewing zone of the windshield is heated via a single heating zone.
It will be apparent to those skilled in the art that there exists a need for a more efficient multi-zone bus bar arrangement for a vehicle window.
An object of this invention is to provide an efficient bus bar arrangement for a heatable vehicle window (e.g., windshield).
Another object of this invention is to provide a bus bar arrangement for a heatable vehicle window, wherein the bus bar arrangement defines at least first and second heating zones.
Another object of this invention is to fulfill one or more of the above-listed objects.
Generally speaking, certain example embodiments of this invention fulfill one or more of the above-listed needs by providing a heatable vehicle windshield including a top edge, a bottom edge, and first and second side edges, the heatable vehicle windshield comprising:
first and second glass substrates laminated to one another with at least a polymer inclusive interlayer therebetween;
a coating located between said first and second substrates, said coating including at least one conductive layer;
first, second, and third conductive bus bars, wherein at least portions of said first, second, and third bus bars are in electrical communication with said conductive layer of said coating, so that when electric current is passed through said conductive layer via bus bars at least a portion of the windshield is heated;
wherein a top portion of said first bus bar and a top portion of said second bus bar are located in spaced apart relation at a top area of said windshield, and said third bus bar is located at a bottom area of said windshield;
wherein a first heating zone is defined by a portion of said coating in electrical communication with and between (i) said top portion of said first bus bar, and (ii) said third bus bar, and a second heating zone is defined by a different portion of said coating in electrical communication with and between (i) said top portion of said second bus bar, and (ii) said third bus bar; and
wherein connection portions of said first and second bus bars are provided proximate or adjacent the bottom edge of the windshield so that corresponding electrical connectors in electrical communication with first, second, and third bus bars, respectively, are each attached to the windshield proximate the bottom edge thereof, at least one of said electrical connectors supplying electric current to said conductive layer said coating via an external power source.
Certain other embodiments of this invention fulfill one or more of the above-listed objects by providing a heatable window comprising:
at least one substrate supporting a coating;
first, second, and third conductive bus bars, wherein at least portions of said first, second, and third bus bars are in electrical communication with a conductive layer of said coating, so that when electric current is passed through said conductive layer via bus bars at least a portion of the window is heated;
wherein a first portion of said first bus bar and a first portion of said second bus bar are located in spaced apart relation from one another at a top or upper area of said window, and said third bus bar is at least partially located at a bottom area of said window;
a first heating zone defined by a first portion of said coating in electrical communication with and between a) said first portion of said first bus bar, and b) said third bus bar;
a second heating zone defined by a second portion of said coating in electrical communication with and between a) said first portion of said second bus bar, and b) said third bus bar; and
wherein connection portions of said first and second bus bars are provided proximate or adjacent a bottom edge of the window so that corresponding electrical connectors in electrical communication with the first, second, and third bus bars, respectively, are each attached to the window proximate the bottom edge thereof, at least one of said electrical connectors supplying electric current to said conductive layer of said coating via an external power source.
Still further embodiments of this invention fulfill one or more of the above-listed needs by providing a heatable window comprising:
at least one substrate supporting a heatable conductive layer; first, second, and third spaced apart bus bars each in electrical communication with said heatable conductive layer;
a first heating zone including a first portion of said conductive layer defined between a top or upper portion of said first bus bar and said third bus bar;
a second heating zone including a different second portion of said conductive layer defined between a top or upper portion of said second bus bar and said third bus bar; and
wherein said top or upper portions of said first and second bus bars, respectively, are located in spaced relation from one another at a top or upper area of said window, and said third bus bar is located at a bottom area of said window.
This invention will now be described with respect to certain example embodiments thereof as illustrated in the following drawings, wherein: